Method of making springs



March 15, 1966 c. H. K. SJOBOHM METHOD OF MAKING SPRINGS 4 Sheets-Sheet1 Original Filed Oct. 19, 1961 IN VENTORS RT H. K. .SJOBOHM,

Attorney v FRANK WZ Miami: 15, Mlfi c. H. K. SJOBOHM 324@238 METHOD OFMAKING SPRINGS Original Filed. Oct. 19. 1961 4 Sheets-Sheet 2 March 15,1966 3,240,238

C. H. K. SJOBOHM METHOD OF MAKING SPRINGS Original Filed Oct. 19, 1961 4Sheets-Sheet 5 INVENTORS CURT H. K. SJOBOHM, 1

FHA/Wig z KOWSK/ M Attorney United States Patent Ofiice 3,Z4@,Z3Patented Mar. 15, 1966 3,240,238 lvlEiHQl) OF MAKING SPRINGS Curt H. K.Sjobohm and Frank W. Zukowslri, Vorcester, Mass, assignors to UnitedStates Steel Corporation, a corporation of Delaware Original applicationOct. 19, 1961, Ser. No. 146,185. Divided and this application Oct. 13,1964, Ser. No.

Claims. (Cl. 140-71) This application, which is a division of myco-pending application Serial No. 146,185, filed October 19, 1961,relates to a method of making springs and more particularly to themaking of magazine springs for rifles. Such springs are made up of aplurality of generally oblong convolutions intermediate the ends withthe first end having a generally square portion whose sides areapproximately the same length as the short side of the oblongconvolutions. The other end of the spring has a curved portion. Prior toour invention this spring was made by using a spiral coiler to make longlengths of oblong convolutions. The long length of convolutions werethen cut into sections of sufficient length to form a single spring. Thefirst end of the spring was then formed in a separate machine, it beingnecessary to bend the one portion of the wire out of its original shapeand to trim the end to the correct length. In making the second end ofthe spring it was necessary to straighten part of a convolution alreadyformed, rebend it to form the curved end and trim it to exact length.The finishing steps in making the spring were diilicult and required agreat deal of labor so that the cost of manufacturing the spring wasvery high. In addition, the reverse bending and straightening withsubsequent reforming resulted in a great number of defective springs. Insome cases the ends of the springs Where heated during the straighteningoperation.

It is therefore a object of our invention to provide a cheap andaccurate method of making magazine springs.

This and other objects will be more apparent after referring to thefollowing specification and attached drawings, in which:

FIGURE 1 is a plan view of a machine for performing a part of the stepsof our method and with center parts omitted for the purpose of clarity;

FIGURE 2 is an elevation of the front end of the machine with partsbroken away and shown in section;

FIGURE 3 is a view taken on the line Illlll of FIG- URE 1;

FIGURE 4 is a view taken on the line IV-IV of FIG- URE 2;

IGURE 5 is a view taken on the line VV of FIG- URE 4;

FIGURE 6 is an enlarged view of the spring winding arbor as attached tothe spindle;

FIGURE 7 is a plan view of the lower part of the arbor;

FIGURE 8 is a schematic view showing the control for a portion of thefeeding mechanism;

FIGURE 9 is a schematic view showing the control for the cut-offmechanism;

FIGURE 10 is a schematic view showing the control for the pitchmechanism;

FIGURE 11 is a view of a spring formed by our in vention;

FIGURE 12 is a plan view of a bending machine used in forming a bend inthe end of a spring; and

FIGURE 13 is an elevation of the machine of FIG- URE 12.

Referring more particularly to the drawings, the reference numeral 2indicates a stand for supporting the machine of FIGURES 1 to 10. A gear4 is attached to a shaft 6 which is rotatably mounted on the stand 2.Power for rotating the gear 4 is provided from any suitable source. Theface of the gear 4 is provided with diametrical guideways 8 foradjustment therein of a head 10 which carries a crank pin 12. One end ofa connecting rod 14 is connected to the crank pin. The other end of theconnecting rod 14 is pivotally connected to a slidable rack 16 which isguided in a horizontal path by means of suitable slideways on thesupporting stand 2. The stroke of the sliding rack may be varied byadjusting the position of the head 10 in the guideways 8. The teeth ofthe rack 16 are'in mesh with the teeth of a pinion 13- which is mountedon a vertical shaft 20. A large gear 22 is rotatably mounted on the topof the shaft 26 and is driven by means of a clutch 24, such as the oneshown in the patent to Thomas No. 1,935,137. The gear 22 is in mesh witha pinion 26 which is secured to a vertical spindle 28. A spring windingarbor 30 is attached to the bottom of spindle 28. A bevel gear 32 ismounted on the free end of shaft 6 and is in mesh with a similar bevelgear 34 mounted on a rotatable shaft 36 which extends toward the frontof the machine. Cams 38 and 40 are mounted on shaft 6 for rotationtherewith. A bracket 42 for the wire feeding mechanism 44 is attached tothe supporting frame 2 between the cam 38 and the front of the machine.The wire feeding mechanism 44 may be of any conventional type and thatshown is that disclosed in Sjobohm Patents No. 2,794,477 dated June 4,1958 and No. 2,919,014 dated December 29, 1959. Other parts of themachine so far described, excet for cam 40, are also similar to thatdisclosed in the Sjobohm patents. Regardless of what type of feedingmechanism is used it will include a slide 46 to which is attached arearwardly extending screw or pin 48. The slide 46 also carries amovable jaw 50 and a stationary jaw 52. The slide 46 is moved toward thefront of the machine by means of cam 38 contacting a roller 54 attachedto the slide and is retracted by means of a spring 56. A cam 58 ismounted on shaft 36 intermediate its length and contacts a roller 60 tomove jaw 50 so as to grip a wire W between jaws 5t) and 52. Since thefeeding mechanism does not per se form any part of the present inventionno further description thereof is necessary. The wire W being fed passesthrough apparatus 62 which permits the wire to feed forwardly butprevents backward movement thereof. Apparatus suitable for this purposeis shown in the patent to Delihanty No. 1,026,567.

A rotatable ratchet wheel 64 is mounted with its axis parallel to thedirection of movement of slide 46. As best shown schematically in FIGURE8 the ratchet wheel 64 includes peripheral teeth 66 and adjustablymounted or removable studs 68 which are adapted selectively to alignwith pin 48. A pawl 70 is pivotally mounted on a slide 72 which isattached to piston rod '74 of a double acting air cylinder 76. A 4-wayvalve 78 operated by cam 4t) controls the flow of air to the cylinder76. A flat spring 80 is mounted in position to bear against the ratchetwheel teeth 66 to provide a braking action and to prevent overtravel ofthe ratchet wheel 64. The slide 72 is mounted for movement on rods 81.

A spur gear 82 mounted on the front end of shaft 36 is in mesh with aspur gear 84 which drives a gear reducer 86 having a shaft 83 extendingfrom both ends thereof. Cams 90 and 92 are mounted on opposite ends ofshaft 88. A standard type wire cutter 94 is mounted on frame 2 andincludes a cutting blade 96 mounted on slide 98 for movement toward andaway from the path of movement of wire W on the feed side of arbor 30.As shown in FIGURE 9 an air cylinder 100 moves the slide 98 on itscutting stroke and a spring 182 retracts the slide 98. A 3-way solenoidvalve 104 controls flow of air to and from the cylinder 100. Flow ofcurrent to solenoid 1048 from power source L1, L2 is controlled by meansof a micro switch 106. Operation of switch 106 is controlled by cam 90.

A pitch lever 108 is pivotally mounted on shaft 36 and is free to rotatethereon. The end of lever 108 adjacent spindle 28 has a downwardlyextending finger 110 thereon. The other end of lever 188 has a slot 112therein for receiving a roller 114 mounted on a slide 116 whichreciprocates in guides 118. The slide 116 is attached to the piston rod120 of a double acting air cylinder 122. As shown in FIGURE 10 air flowto cylinder 122 is controlled by means of a solenoid operated 4-wayvalve 124. Flow of current from power source L1, L2 to solenoid 1248 iscontrolled by a micro switch 126 which has a roller 126R on itsoperating arm. The timing wheel or cam 92 has a plurality of depressions92D around the periphery thereof and the switch 126 will be closed whenthe roller 126R is in any of the depressions 92D and open in the otherpositions. By suitable selection of the length of arc of the depressions92D and the spacing thereof the timing of movement of arm 108 and thetime it remains in down position can be controlled to make differentshapes and sizes of springs. A lug 128 is mounted on the cam 92 and isadapted to contact roller 130R of a micro switch 134 which is mounted incircuit with a solenoid 1328. An arm 134- pivotally mounted adjacent itsends has one end pivotally connected to arm 132 actuated by solenoid1325. The free end of arm 134 has a finger 136 which is adapted to moveinto engagement with and prevent or limit downward movement of the arm108. A spring 138 attached to the bottom of arm 134 returns it toretracted position when solenoid 1328 is deenergized.

As shown in FIGURES 2, 4 and a guide 140 having a semicircular groove142 therein for guiding the wire W is located adjacent the arbor 38 onthe entry side thereof and is mounted on stand 2 in any suitable manner.A hold down guide plate 144 is also mounted on stand 2 with its endabutting guide plate 148 just above groove 142. A guide plate 146 ismounted below plate 144 on the exit side of arbor 30 with a horizontalslot 148 therebetween so as to receive and guide the wire W as it is fedforwardly and for a short are of its travel as it is being formed.

As best shown in FIGURE 6 the arbor 30 is received in an opening 150 inthe bottom of spindle 28 and is adjustably held in place by means of setscrew 152. Vertical pins 153 and 154 are secured to the bottom of arbor30 in a usual manner.

FIGURE 11 shows a magazine spring 155 which can be made by our method.The spring 155 includes an end consisting of slides 156, 157, 158, 159and 160 all in the same plane. The other end of the spring 155 includesa bent portion 161 connected to a long side 162 which in turn isconnected to a short side 163. Between the two ends of the spring 155are a plurality of convolutions each consisting of a long leg 164, ashort leg 165 in the same plane as leg 164, a long leg 166 extending atan angle to leg 164, and a short leg 167 in the same plane as leg 166.

In making the spring 155 a ratchet wheel 64 is provided having pins 68mounted thereon with the proper spacing and projections. A suitable camwheel 92 is also selected and the machine started in operation with thewire W positioned in the feeding mechanism which is in its rear positionready to grip the wire. The stop pin 48 is aligned with a ratchet pin 68since it is desired to feed a short length of wire corresponding to side156. As the cam 58 rotates it causes the jaws to grip the wire Wtherebetween and the rotating cam 38 then causes the slide 46 to moveforwardly, thus feeding the wire between the pins 153 and 154. The arbor38 is rotated in timed relationship with the feed of the wire through anangle of 90 to put a bend in the wire. The jaws are released from thewire W as the cam 58 continues to 4 rotate and the slide retracted byspring 56 as the cam 38 continues its rotation. As the slide 46 ismoving forwardly the cam 46 actuates the valve 78 to a position whereair is delivered to the front of cylinder 76 so as to retract the slide72. As the slide 46 reaches its extreme forward position the cam 46moves out of contact with valve 78 which is then positioned to deliverair to the rear of cylinder 76 so as to move the pawl 70 and advance theratchet wheel 64 a distance equal to one tooth on its periphery. Thispositions a second pin of slightly different length than the first pin68 in alignment with pin 48 so that as the slide retracts pin 48 willabut it. The above operations will be repeated for sides 157 and 158.After side 158 is formed no pin 68 is positioned in line with pin 48since side 159 is longer than sides 156, 157 and 158. Thus the pin 48will contact the side of wheel 64 and a longer length of wire will befed to correspond to the length of side 159. After side 159 has beenformed as described above a pin 68 of the same length as the pin usedfor side 158 will be aligned with pin 48 and the side 168 will befdrmed. After side 16% is formed side 164 is formed in the same manneras side 159. However, in the meantime cam 92 will have been rotating intimed relationship with the other parts of the machine so that theroller 126R will be in a depression 92D. Thus the switch 126 will closeand actuate the arm 188 to contact leg 164 and form the desired pitch inthe leg 164. During this time the wire is free to rotate, but uponcompletion of the pitching action the wire is again gripped by the jaws50 and 52 to retain the pitch and prevent uncoiling affer the pitchfinger is retracted. The pitch finger remains in contact with the wireuntil another tooth or raised portion is reached by the cam 92 to openthe switch 126. This will occur after formation of side 166, sides 165and 167 being formed in the same manner as side 166. The operationsdescribed will continue until formation of side 163 and formation of thebend between sides 162 and 163. At this time lug 128 will close switchto energize solenoid 1328 and move finger 136 under finger 110 so as tolimit movement of finger 110 which has been actuated by cam 92. Whenthese operations have been completed the cam 98 will close switch 106,thus opening valve 104 to cause cutter 96 to cut the wire off of alength from the last bend to include portions 161 and 162. The machineis then ready to form another spring.

In some instances it may also be desired to form a pitch in the shortsides and 167. For this purpose a wedge 168 is mounted beneath the plate144 in the position shown in FIGURES 2, 4 and 5 with its entry end a distance from the axis of the arbor 38 less than the length of sides 164and 166 to its center a distance from the line of travel of the wireless than the length of the short sides 165 and 167. As the wire formingthe long legs is fed forwardly the formed short leg at the end thereofwill contact the wedge 168 and direct it downwardly. Thus when the wireis relieved from the grip of the jaws 50 and 52 it will be rotated aboutits axis so that the pitch is formed in the short leg.

The looped portion 161 is formed in the wire in any suitable manner. Forexample, the apparatus shown in FIGURES l2 and 13 may be used. Thisincludes a base 170 having a pinion 172 rotatably mounted thereon insuitable bearings. A rack 174 in mesh with pinion 172 is mounted forsliding movement in guides 176 and is actuated by means of a footoperated air cylinder 178. An abutment 180 at the end of rack 174opposite cylinder 178 carries a guide pin 182 for receiving a spring184. A guide pin 186 mounted on an abutment 188 carried by base 178supports the other end of spring 182, which re turns the rack 174 whenair is released from cylinder 178. A pin 198 is mounted on the axis ofpinion 172 and a pin 192 is mounted on an extension of pinion 172 inspaced relationship with pin 190. With the pin 192 in the full lineposition shown in FIGURE 13 the operator positions the wire containingportions 161 and 162 as shown between pins 190 and 192 and then actuatescylinder 178 to rotate the pinion 172 with the pin 192 moving to thebroken line position shown so as to form the bend therein. Air is thenreleased from cylinder 178 permitting spring 184 to return the rack 174and pinion 172 to their original position.

While one embodiment of our invention has been shown and described, itwill be apparent that other adaptations and modifications may be madewithout departing from the scope of the following claims.

We claim:

1. The method of making a plurality of magazine springs each having aplurality of generally oblong convolutions, said method comprisingproviding a wire of such length as to provide for a plurality ofsprings, feeding a length of wire sufficient to form a long side of aconvolution to an oscillating arbor having means for receiving the wire,then feeding a length of wire sufiicient to form a short side of aconvolution, continuing the last two steps and correlating the feed withthe oscillations of the arbor while forming the desired pitch in theconvolutions until all of the convolutions in a spring are formed, thensevering the wire, and repeating the above operations to form anotherspring.

2. The method of making a plurality of magazine springs each having aplurality of gene-rally rectangular convolutions intemediate its ends, afirst end having a generally rectangular portion of differetnconfiguration than the rectangular convolutions connected to the firstof said rectangular convolutinos and a second end having a curvedportion connected to the last of said rectangular convolutions, saidmethod comprising providing a wire of such length as to provide to raplurality of springs, feeding the wire in successive steps to anoscillating arbor having means for receiving the wire, the incrementsand length of feed being correlated with the oscillations of the arborto form the rectangular portion of the first end of the spring,continuing feeding of the wire in successive steps of such lengthcorrelated with the oscillations of the arbor to form the intermediateconvolutions and forming the desired pitch in said intermediateconvolutions, after the intermediate convolutions are formed severingthe wire at a distance from the intermediate portions to provide astraight length of wire of suflicient length to include the second endof said spring, bending the said straight end to provide the said curvedportion, and repeating the above operations to form further springs fromthe said length of wire.

3. The method of making a plurality of magazine springs each having aplurality of generally oblong convolutions intermediate its ends, afirst end having a generally square portion connected to the first ofsaid oblong convolutions and a second end having a curved portionconnected to the last of said oblong convolutions, said methodcomprising providing a wire of such length as to provide for a pluralityof springs, feeding the wire three successive equal steps to anoscillating arbor having means for receiving the wire and correlatingthe feed with the oscillations of the arbor to form the said generallysquare portion, then feeding a length of wire sufiicient to form a longside of an intermediate convolution, then feeding a length of Wiresuificient to form a short side of an intermediate convolution,continuing the last two steps until all the intermediate convolutionsare formed while forming the desired pitch in said intermediateconvolutions, after the intermediate convolutions are formed severingthe wire at a distance from the intermediate portions to provide astraight length of wire of sufficient length to include the second endof said spring, bending the said straight end to provide the said curvedportion, and repeating the above operations to form another spring.

4. The method of making a plurality of magazine springs each having aplurality of generally rectangular convolutions intermediate its ends, afirst end and a second end, the first and second ends having shapesdiiferent than the intermediate convolutions, said method comprisingproviding a wire of such length as to provide for a plurality ofsprings, feeding the wire in successive steps to an oscillating arborhaving means for receiving the wire, the increments and length of feedbeing correlated with the oscillations of the arbor to form the firstend of the spring, continuing feeding of the wire in successive steps oflengths varying from the length fed in the initial feeding step andcorrelating the feed with the oscillations of the arbor to form theintermediate convolutions while forming the desired pitch in saidintermediate convolutions, after the intermediate convolutions areformed severing the wire at a distance from the intermediate portions toprovide a straight length of wire of suflicient length to form thesecond end of said spring, and repeating the above operations to formfurther springs from the said length of wire.

5. The method of making a plurality of magazine springs each having aplurality of generally rectangular convolutions intermediate its ends, afirst end having a generally rectangular portion smaller than theintermediate convolutions and a second end having a different shape thanthe convolutions and said first end, said method comprising providing awire of such length as to provide for a plurality of springs, feedingthe wire in successive steps to an oscillating arbor having means forreceiving the wire, the increments and length of feed being correlatedwith the oscillations of the arbor to form the first end of the spring,continuing feeding of the Wire in successive steps of lengths varyingfrom the length fed in the initial feeding step and correlating the feedwith the oscillations of the arbor to form the intermediate convolutionswhile forming the desired pitch in said intermediate convolutions, afterthe intermediate convolutions are formed severing the wire at a distancefrom the intermediate portions to provide a straight length of wire ofsuflicient length to include the second end of said spring, andrepeating the above operations to form further springs from the saidlength of wire.

References Cited by the Examiner UNITED STATES PATENTS 3,045,740 7/1962Davis 15364 3,067,780 12/1962 Kahn -103 CHARLES W. LANHAM, PrimaryExaminer.

1. THE METHOD OF MAKING A PLURALITY OF MAGAZINE SPRINGS EACH HAVING A PLURALITY OF GENERALLY OBLONG CONVOLUTIONS, SAID METHOD COMPRISING PROVIDING A WIRE OF SUCH LENGTH AS TO PROVIDE FOR A PLURALITY OF SPRINGS, FEEDING A LENGTH OF WIRE SUFFICIENT TO FORM A LONG SIDE OF A CONVOLUTION TO AN OSCILLATION ARBOR HAVING MEANS FOR RECEIVING THE WIRE, THEN FEEDING A LENGTH OF WIRE SUFFICIENT TO FORM A SHORT SIDE OF A CONVOLUTION, CONTINUING THE LAST TWO STEPS AND CORRELATING THE FEED WITH THE OSCILLATIONS OF THE ARBOR WHILE FORMING THE DESIRED PITCH IN THE CONVOLUTIONS UNTIL ALL OF THE CONVOLUTIONS IN A SPRING ARE FORMED, THEN SEVERING THE 